The theft of the vehicle and the welder sounds fishy.... How do these trucks start without communicating to the key?
Cloning the key.
Using a directional antenna and amp to extend range for challenge/response between they key and truck.
Tow truck Jacking.
Where there's a will, there's a way.
As for deterrents, the more gaudy and visible they are, the more effective they will be. this is where crap like the club work. Kill switches are effective at drive off thefts if done well.
Geofencing with the hotspot/cellular service is a great way to find out quickly, then you can get FCA to remote kill, if equipped.
Used to be having a manual transmission was also a deterrent. maybe now you have to do silly stuff like relocate the triggering relay for pushbutton start to somewhere else, like the seat controls (beyond my skill level).
get a SGW bypass module installed and a raspi connected to the car OBD that will kill the ignition if it doesn't get a bluetooth link to your phone. Sky's the limit with crazy interrupts.